Magnets and Motors

• The Magnets and Motors kit is designed for 5-6 grade. It's objectives are to learn magnets put forces on each other, how to buld a compass, current carrying wires produce magnetism, and how motors can be made from magnets.
• In general, this kit can be divided into four sections:
  • Intro: How do electric motors work? What do they have to do with magnets?
  • How do magnets work? How can we use magnets to create motion?
  • How can we use electricity to make magnets?
  • How do electric motors use electricity and magnets to make motion?

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Lessons

Lesson 1: Getting Started

• Students list their knowledge of magnets and motors and learn how to keep records in a student notebook.
• Preparation: Copies of Activity Sheet 1. Arrange newsprint for brainstorming
• Demo: Show an electric motor, with a straw to act as a propellor. How does it work? What is inside the motor that makes it work? The motor can be viewed as a mystery box: electricity goes in, spinning motion comes out. How is the electricity converted into motion?

Lesson 2: What Can Magnets Do

• Students learn properties and uses of magnets by playing with them.
• Preparation: Cut 30cm piece of string for each student. Designate material station. Prepare demonstration from Step 1 of procedure section.
• Idea: Treat this as a way for the students to design "tricks" that they can do with magnets. They can play with the magnets, then at the end of the class, each group can show off their tricks.

Lesson 3: How Can You Find Out What Magnets Do

• Students investigate a 'mystery box' full of stuff and try to learn what is inside using magnets.
• Preparation: Provide one packet of materials for every four students. Construct mystery boxes or have students make their own.

• Extensions:
  • Incorporate a larger mystery box lesson into this lesson:
    • Note: Have someone other than yourself or the teacher put together the mystery boxes, so that no one in the classroom knows what is actually inside.
    • Begin with one standard mystery box, containing a loose assortment of objects. The students can manipulate the box and listen to the sounds to figure out what's inside.
    • Next, introduce a mystery box that contains only taped-down objects. Have the objects made out of magnetic materials (including magnets themselves). The students can tell there's stuff inside because of the weight, but moving the box doesn't produce any sound. How else can we figure out what is inside? (use magnets and magnetic materials to see what parts of the box they are attracted to).
    • Have the students work with the package of magnetic and non-magnetic materials, to figure out what is and isn't magnetic.
    • Pass out a series of mystery boxes, which contain only objects from the students' packets. Have the students figure out which objects are inside which boxes. These should be the only mystery boxes (if any) that the students are allowed to open at the end of the lesson.
      • Note: When using small, long objects such as pins and nails, it is a good idea to tape the inside corners of the boxes so these objects don't fall out.
  • An extension on why magnetic tape is magnetic, and how tape players work. This could also be incorporated into a lesson on how speakers and microphones work.

Lesson 4: Measuring Magnets

• Students measure the strength of magnets by seeing how many washers a number of magnets can hold off the ground.
• Preparation: Prepare all materials, make one copy of Activity Sheet 2 for each student.
• Note: Sometimes students have a hard time understanding that we're using the apparatus and washers to test the strength of the magnets. Emphasize that the apparatus is just needed to suspend the magnets in the air so that we can hang weights from it. The more weight we can hang from it without the weight fallling, the stronger the magnets are.
• Another note: A few students may stack the magnets along the tongue depressor, or in a pyramid pattern instead of a single stack. You can direct the students to all stack the magnets the same, or you can use this as a graphing lesson: compare graphs for the single stack magnets vs. the pyramid-stacked magnets... do they look different? Why?

Lesson 5: Building a Compass

• Students build a compass out of a straw nail, string, a cup, and magnets.
• Preparation: Gather all materials, make demonstration compass.
  • Because this kit comes in a single box, some of the compasses will be demagnetized or reversed due to coming into contact with the magnets in the box. Before beginning the class, try to find compasses that all point in the same direction.
• Note: The toughest part of this lesson seems to be getting the compass balanced so that it can spin freely. Some tips for this:
  • The pin must not be pushed too far through the straw. Only the tip of the pin should be pushed through the straw.
  • The magnets must "hang down" from the straw. Make sure that the piece of wire wrapped around the magnets comes off the top of the magnet, not from the middle. Magnets attached in a "dumbbell" fashion are much harder to balance.
  • To ensure that the magnets stay in place, have the students flare out the loop of wire a bit so that it fits snugly in the end of the straw.
  • If the compass leans to one side, pull out the magnet on the high side (or push in the magnet on the low side).
  • If the compass tilts along the axis of the straw, twist both magnets upwards, so that they are more in line with the pin.

Lesson 6: Using a Compass

• Students use their balance compasses and provided compasses to determine which pole of the magnet points north.
• Preparation: Display large map or globe and determine the North side of the room.
• Classrooms sometimes have too many magnetic things (TVs, steel desks, etc.) for the compasses to point north. You may want to do this lesson in an open area, such as a gym or playground, instead.
• Extension: How can you use a magnet to make the compass spin? This will answer the question "How can we use magnets to create motion?", and the students like doing this with their compasses.

Lesson 7: Creating Magnetism Through Electricity

• Students learn that current carrying wires also produce magnetism.
• Preparation: Cut three 20cm and one 80cm piece of wire for each student, and strip the ends of the wires, and gather all other materials for experiment.
• Note: This lesson can be combined with Lesson 8.

Lesson 8: Making Magnets with Electricity

• Students use a coil of wire and wrap wire around a bolt to make electromagnets.
• Preparation: Same as Lesson 7 with the addition of bolts.
  • The bolts may contain residual magnetism, which will affect the compass whether or not the current is flowing. To get rid of the residual magnetism, bounce each bolt on the floor a few times.

Lesson 9: Design Experiment to Test Strength of Electromagnet

• Students learn how to design an experiment to test what variables change the strength of an electromagnet, including number of turns around the bolt and how many batteries.
• Preparation: Make copies of Activity Sheet 3 for each student and Activity Sheet 4 for each team. Cut colored construction paper into cards for each team; six yellow cards for variables, one pink card for the variable to be investigated, and one large blue card for description of what students will do.
• This is a good lesson to turn into a work sample. You may want to reserve 2 class periods for this lesson, to allow the students to re-design any experiments that may not work.

Lesson 10: Testing the Electromagnet

• Students carry out the experiment they designed in Lesson 9.
• Preparation: Check Planning Boards from Lesson 9 for materials for each team and prepare the materials needed for this lesson. You may want to try out a few experiments on your own.

Lesson 11: Showing Others What You Have Learned

• Students graph their results from Lesson 11 and present their graphs to others.
• Preparation: Make copy of Activity Sheet 5 for each student. Check students data to see if some teas may have trouble.

Lesson 12: Making a Motor

• Students use and electromagnetic coil and a switch to make a compass move like a motor.
• Preparation: Prepare materials and make a motor for yourself to spot troubleshooting.

Lesson 13: Building a Spinning Coil Motor

• Students build a working electric motor from inexpensive materials.
• Preparation: Prepare materials and build your own motor for troubleshooting.

Lesson 14: What's Inside an Electric Motor

• Students take apart and investigate a commercial electric motor.
• Extension: Making a robot.

Lesson 15: How Does a Motor Work

• Students reassemble the motor they took apart to test their understanding.
• Preparation: You may have to construct 'double stranded' hook-up wires (see page 96 of teacher guide).

Lesson 16: Generating Electricity

• Students use a generator to power the motor and to light a bulb.
• Preparation: Prepare a presentation on the concept of generalizing electricity and magnetism (see steps 1 and 2 in the Procedure section).

Prepared by Nathan Kuwada, Fall 2007


Magnet and Motor Demo Ideas
Magnet and Motor Files

Fellows Who Have Taught This Kit:
Charlie
Jen